全文获取类型
收费全文 | 109篇 |
免费 | 3篇 |
专业分类
教育 | 56篇 |
科学研究 | 36篇 |
各国文化 | 1篇 |
体育 | 6篇 |
信息传播 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有112条查询结果,搜索用时 274 毫秒
31.
Ashley K. Smith Watts Deepika Patel Robin P. Corley Naomi P. Friedman John K. Hewitt JoAnn L. Robinson Soo H. Rhee 《Child development》2014,85(4):1569-1585
Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association remains unclear. This study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive language abilities were collected from 816 twins at ages 14, 20, and 24 months. Growth and regression models were fit to the data to assess the longitudinal associations between behavioral inhibition and language development from 14 to 24 months. Overall, there were significant associations between behavioral inhibition and expressive language, and minimal associations with receptive language, indicating that the association is better explained by reticence to respond rather than deficient language development. 相似文献
32.
Apoorva Patel 《Resonance》2011,16(9):821-835
The driving force in the pursuit for quantum computation is the exciting possibility that quantum algorithms can be more efficient
than their classical analogues. Research on the subject has unraveled several aspects of how that can happen. Clever quantum
algorithms have been discovered in recent years, although not systematically, and the field remains under active investigation.
Richard Feynman was one of the pioneers who foresaw the power of quantum computers. In this issue dedicated to him, I give
an introduction to how particle and wave aspects contribute to the power of quantum computers. Shor’s and Grover’s algorithms
are analysed as examples. 相似文献
33.
Preschoolers’ conceptual understanding and procedural skills were examined so as to explore the role of number‐words and concept–procedure interactions in their additional knowledge. Eighteen three‐ to four‐year‐olds and 24 four‐ to five‐year‐olds judged commutativity and associativity principles and solved two‐term problems involving number words and unknown numbers. The older preschoolers outperformed younger preschoolers in judging concepts involving unknown numbers and children made more accurate commutativity than associativity judgements. Children with conceptual profiles indicating a strong understanding of concepts applied to unknown numbers were more accurate at solving number‐word problems than those with a poor conceptual understanding. The findings suggest that an important mathematical development during the preschool years may be learning to appreciate addition concepts as general principles that apply when exact numbers are unknown. 相似文献
34.
35.
The relationship between bowling action classification and three-dimensional lower trunk motion in fast bowlers in cricket 总被引:1,自引:1,他引:0
Lower back injuries, specifically lumbar stress fractures, account for the most lost playing time in professional cricket. The aims of this study were to quantify the proportion of lower trunk motion used during the delivery stride of fast bowling and to examine the relationship between the current fast bowling action classification system and potentially injurious kinematics of the lower trunk. Three-dimensional kinematic data were collected from 50 male professional fast bowlers during a standing active range of motion trial and three fast bowling trials. A high percentage of the fast bowlers used a mixed bowling action attributable to having shoulder counter-rotation greater than 30 degrees. The greatest proportion of lower trunk extension (26%), contralateral side-flexion (129%), and ipsilateral rotation (79%) was used during the front foot contact phase of the fast bowling delivery stride. There was no significant difference in the proportions of available lower trunk extension, contralateral side-flexion, and ipsilateral rotation range of motion used during fast bowling by mixed and non-mixed action bowlers. Motion of the lower trunk, particularly side-flexion, during front foot contact, in addition to variables previously known to be related to back injury (e.g. shoulder counter-rotation), should be examined in future cross-sectional and prospective studies examining the fast bowling action and low back injury. 相似文献
36.
John DuBose Xinyu Lu Saurin Patel Shizhi Qian Sang Woo Joo Xiangchun Xuan 《Biomicrofluidics》2014,8(1)
Shape is an intrinsic marker of cell cycle, an important factor for identifying a bioparticle, and also a useful indicator of cell state for disease diagnostics. Therefore, shape can be a specific marker in label-free particle and cell separation for various chemical and biological applications. We demonstrate in this work a continuous-flow electrical sorting of spherical and peanut-shaped particles of similar volumes in an asymmetric double-spiral microchannel. It exploits curvature-induced dielectrophoresis to focus particles to a tight stream in the first spiral without any sheath flow and subsequently displace them to shape-dependent flow paths in the second spiral without any external force. We also develop a numerical model to simulate and understand this shape-based particle sorting in spiral microchannels. The predicted particle trajectories agree qualitatively with the experimental observation. 相似文献
37.
Chavan VU Durgawale PP Sayyed AK Sontakke AV Attar NR Patel SB Patil SR Nilakhe SD 《Indian journal of clinical biochemistry : IJCB》2011,26(3):283-289
Twenty-four hour urinary albumin excretion (UAE) is considered as gold standard method for albuminuria measurement, but collection
of 24-h urine is inconvenient. The aim of present study was to evaluate whether albumin: creatinine ratio (ACR) and urinary
albumin concentration (UAC) in different spot urine samples correlate or not with 24-h UAE for screening of microalbuminuria
in type 2 diabetic patients. We collected first morning void (FMV), random urine sample (RUS) and 24-h urine, separately on
consecutive days from 104 type 2 diabetic patients. ACR and UAC in each spot urine sample compared with 24-h UAE with regard
to Pearson correlation coefficient. Pearson’s correlation of albumin: creatinine ratio (ACR) with 24-h UAE was (r = 0.802 and 0.623) in first morning void (FMV) and random urine sample (RUS), respectively. Pearson’s correlation coefficient
of urinary albumin concentration (UAC) compared with 24-h UAE was (r = 0.943 and 0.920), in FMV and RUS, respectively, P < 0.01. Results revealed that values in first morning void (FMV) were better correlated with 24-h urinary albumin excretion
(UAE), than the values in random urine sample (RUS). We conclude that the first morning void (FMV) may be able to replace
24-h urine collection, preferably urinary albumin concentration (UAC) in the initial screening of microalbuminuria in diabetic
patients. 相似文献
38.
Vidya Akhileshwar Samir P. Patel Surendra S. Katyare 《Indian journal of clinical biochemistry : IJCB》2007,22(1):84-90
Studies were carried out to examine and compare the effects of alloxan-diabetes on reactive oxygen species (ROS) related parameters
in the heart from male and female rats. Effects of insulin treatment were also evaluated. The diabetic state severely compromised
the ROS defense mechanism in the cardiac tissue and the effects were more pronounced in the female than in the male rats.
There was several fold increase in the xanthine oxidase (XO) activity in general and the magnitude of increase was higher
in the females; insulin treatment resulted in further increase in the XO activity. The glucose-6-phosphate dehydrogenase (G6PDH)
and catalase activities decreased and the reduced glutathione (GSH) content in mitochondria was completely depleted in diabetic
state with significant decrease in the GSH levels in the post-mitochondrial fraction; the effect was more pronounced in the
females. The superoxide dismutase (SOD) and glutathione peroxidase (GPox) activities increased in the diabetic state to a
greater extent in male rats. Insulin treatment had restorative action only on some parameters. In conclusion, our results
suggest that diabetic state may further compromise the weak ROS defense systems in the heart thus initiating a lesion at the
level of mitochondria which ultimately leads to cardiomyopathy and the effects are especially more pronounced in the females.
Our results also pointed out that insulin treatment was ineffective in restoring ROS related parameters. 相似文献
39.
Paola Giuri Myriam Mariani Gustavo Crespi Dominique Francoz Walter Garcia-Fontes Raul Gonzales Karin Hoisl Alessandra Luzzi Lionel Nesta Önder Nomaler Pari Patel Bart Verspagen 《Research Policy》2007,36(8):1107-1127
Based on a survey of the inventors of 9017 European patented inventions, this paper provides new information about the characteristics of European inventors, the sources of their knowledge, the importance of formal and informal collaborations, the motivations to invent, and the actual use and economic value of the patents. 相似文献
40.
R.V. Patel 《Journal of The Franklin Institute》1984,318(2):123-141
This paper describes a computational method for solving the problem of eigenvalue assignment in a multi-input linear system. The given system is first reduced to an upper block Hessenberg form by means of orthogonal state coordinate transformations. It is then shown how a sequence of state feedback matrices and orthogonal state coordinate transformations can be applied to obtain a block triangular structure for the resulting state matrix, where the matrices on the diagonal are square matrices in upper Hessenberg form and of dimensions equal to the controllability indices of the multi-input system. Furthermore, the structure of the corresponding input matrix is such that the problem of eigenvalue assignment in the multi-input system can be reduced to several single-input eigenvalue assignment problems where the dimensions of the single-input systems are equal to the controllability indices of the multi-input system. 相似文献